Question

4. A 62.0-kg person, standing on the diving board, dives straight down into the water. Just before striking the water, her speed is 5.50 m/s. At a time of 1.65 s after she enters the water, her speed is reduced to 1.10 m/s. What is the net average force (magnitude and direction) that acts on her when she is in the water?

Answer 1

To solve this problem it is necessary to apply the concepts related to the Moment. The moment in terms of the Force and the time can be expressed as

$\Delta P = F\Delta t$

F = Force

$\Delta t = Time$

At the same time the moment can be expressed in terms of mass and velocity, mathematically it can be given as

$P = m \Delta v$

Where

m = Mass

$\Delta v =$ Change in velocity

Our values are given as

$\Delta t=1.65s$

By equating the two equations we can find the Force,

$F\Delta t = m\Delta v$

$F = \frac{m\Delta v}{\Delta t}$

$F = \frac{62(1.1-5.5)}{1.65}$

Therefore, the net average force will be:

$F = - 165N$

The negative symbol indicates that the direction of the force is upwards.